How to set expiry time on a Redis key using redis-py?

[YeshitaMotwani]

I want to store a key-value pair in Redis with an automatic expiry time
using the redis-py library in Python.

For example, I want a session token to expire after 30 minutes.

What is the correct way to do this using redis-py?

[lakshit2234]

You can set expiry time in two ways using redis-py:

Option 1 — setex() (set + expiry in one call):

import redis

r = redis.Redis(host='localhost', port=6379, db=0)

# Store key with 30 minute expiry (1800 seconds)
r.setex('session_token', 1800, 'your_token_value')

Option 2 — set() with ex parameter:

r.set('session_token', 'your_token_value', ex=1800)

Option 3 — Set key first, then add expiry with expire():

r.set('session_token', 'your_token_value')
r.expire('session_token', 1800)  # seconds

Check remaining TTL:

ttl = r.ttl('session_token')
print(ttl)  # seconds remaining, -1 = no expiry, -2 = key doesn't exist

For millisecond precision use pexpire():

r.set('session_token', 'your_token_value')
r.pexpire('session_token', 1800000)  # milliseconds

setex() or set(..., ex=...) are the most common approaches for session tokens.

[eeshsaxena]

You can set an expiry time on a Redis key using redis-py in a few ways depending on your use case.

Option 1: Set key with expiry in one command using setex

This sets the key and expiry atomically:

import redis

r = redis.Redis(host='localhost', port=6379, db=0)

# setex(name, time_in_seconds, value)
r.setex('session_token', 1800, 'abc123xyz')  # expires in 30 minutes

Option 2: Use set with ex parameter (recommended)

The set command accepts ex (seconds), px (milliseconds), or exat (Unix timestamp):

r.set('session_token', 'abc123xyz', ex=1800)         # 30 minutes in seconds
r.set('session_token', 'abc123xyz', px=1800000)      # 30 minutes in milliseconds
r.set('session_token', 'abc123xyz', exat=1754000000) # specific Unix timestamp

Option 3: Set expiry separately using expire

If the key already exists and you want to add or update the TTL:

r.set('session_token', 'abc123xyz')
r.expire('session_token', 1800)  # set TTL to 30 minutes

Check remaining TTL:

ttl = r.ttl('session_token')
# returns seconds remaining
# -1 if no expiry set
# -2 if key does not exist
print(ttl)

For session tokens, Option 2 with set(..., ex=1800) is the best pattern since it is atomic. Setting the key and expiry in two separate commands (Option 3) has a small race condition window where the key could exist without an expiry if the process crashes between the two calls.